Fluid operated clutch control system having latch member

Abstract

Provided is an improved fluid operated clutch control system having a latch member operable to lock the clutch in a selected condition of engagement or disengagement when the fluid pressure falls below a predetermined minimum value. In one embodiment a system (100) is provided in which a latch member (26) is controlled by fluid pressure in a channel (36) in a stationary wall housing (10). In another embodiment, a system (200) is provided in which a latch member (62) is controlled by the combination of fluid pressure sensed by a sensor (64) and the energization and de-energization of a solenoid (60) and, in yet another embodiment, a system (300) is provided with a latch member (62) that is controlled by the energization and de-energization of a solenoid (60).

What is claimed: 
     
       1. An improved control system for a fluid operated clutch of the type including linkage operable to effect a condition of engagement or disengagement thereof, said system including first resilient biasing means operatively connected to the linkage and a movable member actuated by pressurized fluid having one end disposed within a fluid chamber contained within a stationary housing wall operably connected to the linkage, said system operable such that the first biasing means is adapted to cause the linkage to effect a selected condition of engagement or disengagement of the clutch and the movable member is adapted to correspondingly cause the linkage to effect a selected condition of disengagement or engagement of the clutch when the movable member is actuated by fluid pressure operable to create a force sufficient to overcome the first biasing means, and said improvement characterized by said system including means for latching, the movable member at a preselected position when the fluid pressure falls below a predetermined minimum value, said latching means comprising: an opening through the housing wall;   engagement means on the movable member facing towards the housing wall and registerable with the housing wall opening;   a latch member extending through the housing wall opening and lockingly engageable with the movable member engagement means at the preselected position;   second resilient biasing means operable to urge the latch member into engagement with the movable member engagement means in registration therewith;   a contact surface on the latch member facing towards the chamber;   a channel extending through the housing wall between the fluid chamber and the contact surface; and   a pin movable disposed between the channel and the latch member contact surface, said pin operable to engage said contact surface and impart the force thereagainst operable to overcome the second resilient biasing means when the fluid pressure in the channel is above the predetermined minimum value;   said latching means operable such that, when the fluid pressure in the channel is above the predetermined minimum value, the resultant force of the pin against the contact surface is effective to overcome the second resilient biasing means and prevent the latch member from engaging the movable member engagement means and, when the fluid pressure in the channel between the chamber and the pin is below the predetermined minimum value, the second resilient biasing means is operable to urge the latch member into engagement with the movable member engagement means and lock the movable member at the preselected position.   
     
     
       2. The system of claim 1, wherein the movable member engagement means is an open-sided groove. 
     
     
       3. The system of claim 1, wherein the movable member is a piston. 
     
     
       4. The system of claim 1, wherein the first resilient biasing means is a spring. 
     
     
       5. The system of claim 1, wherein the first and second resilient biasing means are springs. 
     
     
       6. The system of claim 1, wherein the movable member includes a tapered surface operable to urge the latch member outwardly from the fluid chamber upon engagement therewith. 
     
     
       7. The system of claim 6 wherein the latch member includes a tapered surface engagable with the movable member tapered surface. 
     
     
       8. The system of claim 1, wherein the movable member engagement means is more than one open-sided groove. 
     
     
       9. An improved control system for a fluid operated clutch of the type including linkage operable to effect a condition of engagement or disengagement thereof, said system including first resilient biasing means operatively connected to the linkage and a movable member actuated by pressurized fluid having one end disposed within a fluid chamber contained within a stationary housing wall operably connected to the linkage, said system operable such that the first biasing means is adapted to cause the engagement or disengagement of the clutch and the movable member is adapted to correspondingly cause the linkage to effect a selected condition of disengagement or engagement of the clutch when the movable member is actuated by fluid pressure operable to create a force sufficient to overcome the first biasing means, and said improvement characterized by said system including means for latching, the movable member at a preselected position, said latching means comprising: an opening through the housing wall;   engagement means on the movable member facing towards the housing wall and registerable with the housing wall opening;   a latch member extending through the housing wall opening and lockingly engageable with the movable member engagement means at the preselected position;   a fluid pressure sealing member disposed about the latch member within the opening through the housing wall;   means for providing fluid communication between the fluid chamber and the opening through the housing wall;   second resilient biasing means operable to urge the latch member into engagement with the movable member engagement means in registration therewith;   said latching means operable such that when the fluid pressure in the chamber is above a predetermined minimum the resilient force upon the latch member between the chamber and the sealing member is operative to overcome the second resilient biasing means and prevent the latch member from engaging the movable member engagement means and, when the fluid pressure is below the predetermined minimum, the second resilient biasing means urges the latch member into engagement with the movable member engagement means and locks movable member at the preselected position.